Does running really ruin your knees?

Everyone knows that person who loves to pass on unsubstantiated bits of rumour with the confidence of a fact. "People swear by them… Sometimes they even get attached to these myths like they would to their loved ones and are offended if someone even raises a doubt," says Rujuta Diwekar, nutritionist to stars like our March cover girl Kareena Kapoor Khan.

"But the fact remains that myths are what they are — misinterpretations, misunderstandings and oversimplifications," explains Diwekar in her latest book, Don't Lose Out, Work Out. To fight them, she says, "You must understand why they exist and learn why you should not believe what 'they say'."

Here are the top five exercise urban legends she debunks.

Spot reduction

Diwekar calls this phenomenon "the mother of all myths". Trying to 'burn' fat with excessive crunches, side kicks and leg lifts is not the way to go. While these exercises should be part of your regime, "it can't be the only thing you do in the gym," she says. "You can do two or three sets of 10-15 reps once in a week or two weeks. That way it will serve the purpose of moving muscles in that specific angle and not overload your joints."

Is running bad for your knees?

There is a risk of knee injury with running, but "not so much because you ran, but because you gave your running very little thought," says Diwekar.

"Stretching and strengthening the muscles involved in running is crucial," she says. "Without adequate strength and flexibility, you would injure your knee even if you were not running and just brisk walking."

Weight training makes you bulky

"The very idea of going to the gym is to bulk up; technically it's called hypertrophy or growth of muscles," she explains.

She understands that fear looking disproportionately muscled, but that's not what weight training results in. Instead, she says, it makes you a better fat-burning machine and builds your bone density.

Suryanamaskars are not enough

While Diwekar agrees that suryanamaskars have their benefits, doing a 100 of them will lead to you focusing more on the number rather than the right technique.

Her advice: "Train under a teacher who doesn't push you to achieve a number but pushes you to get your posture right in each of the asanas and teaches you how to breathe through the sequence."

Sweating melts the fat

That's not how the body works, says Diwekar. "Sweat too much and you won't get less fat or more pure or detoxed, but plain dehydrated."

"Exercising in steam rooms or heated environments or without air-conditioning beats the very purpose of exercise," she adds. "If you are going to spend your time exercising, you would want to optimise or get the best out of your body. Instead you are spending more energy or calories thermo-regulating and not as much in muscle fibre recruitment or performance."